Serotonin Depletion-Induced Maladaptive Aggression Requires the Presence of Androgens

The sex hormone testosterone and the neurotransmitter serotonin exert opposite effects on several aspects of behavior including territorial aggression. It is however not settled if testosterone exerts its pro-aggressive effects by reducing serotonin transmission and/or if the anti-aggressive effect of serotonin requires the presence of the androgen. Using the resident intruder test, we now show that administration of the serotonin synthesis inhibitor parachlorophenylalanine (300 mg/kg x 3 days) increases the total time of attack as well as the percentage amount of social behavior spent on attack but not that spent on threat - i.e. that it induces a pattern of unrestricted, maladaptive aggression - in gonadectomized C57Bl/6 male mice receiving testosterone replacement; in contrast, it failed to reinstate aggression in those not given testosterone. Whereas these results suggest the pro-aggressive effect of testosterone to be independent of serotonin, and not caused by an inhibition of serotonergic activity, the pCPA-induced induction of maladaptive aggression appears to require the presence of the hormone. In line with these findings, pCPA enhanced the total time of attack as well the relative time spent on attacks but not threats also in wild-type gonadally intact male C57Bl/6 mice, but failed to reinstate aggression in mice rendered hypo-aggressive by early knock-out of androgen receptors in the brain (AR(NesDel) mice). We conclude that androgenic deficiency does not dampen aggression by unleashing an anti-aggressive serotonergic influence; instead serotonin seems to modulate aggressive behavior by exerting a parallel-coupled inhibitory role on androgen-driven aggression, which is irrelevant in the absence of the hormone, and the arresting of which leads to enhanced maladaptive aggression

The Hungry Stomach: Physiology, Disease, and Drug Development Opportunities

During hunger, a series of high-amplitude contractions of the stomach and small intestine (phase III), which form part of a cycle of quiescence and contractions (known as the migrating motor complex, MMC), play a “housekeeping” role prior to the next meal, and may contribute toward the development of hunger. Several gastrointestinal (GI) hormones are associated with phase III MMC activity, but currently the most prominent is motilin, thought to at least partly mediate phase III contractions of the gastric MMC. Additional GI endocrine and neuronal systems play even more powerful roles in the development of hunger. In particular, the ghrelin-precursor gene is proving to have a complex physiology, giving rise to three different products: ghrelin itself, which is formed from a post-translational modification of des-acyl-ghrelin, and obestatin. The receptors acted on by des-acyl-ghrelin and by obestatin are currently unknown but both these peptides seem able to exert actions which oppose that of ghrelin, either indirectly or directly. An increased understanding of the actions of these peptides is helping to unravel a number of different eating disorders and providing opportunities for the discovery of new drugs to regulate dysfunctional gastric behaviors and appetite. To date, ghrelin and motilin receptor agonists and antagonists have been described. The most advanced are compounds which activate the ghrelin and motilin receptors which are being progressed for disorders associated with gastric hypomotility

Negative influence of a threatened species on ecological status classification: A case study of the influence of European eel within the Swedish fish index VIX

Biological indicators are important quality elements for classification of ecological status of water bodies ac-cording to the European Water Framework Directive. Multimetric indices are commonly regarded as robust and reliable indicators of human impact and are often used as quality elements. In fish-based indices, species are often grouped into guilds based on general tolerance to common anthropogenic pressures, with higher pro-portion of tolerant species being indicative of degraded systems. Within the Swedish electrofishing index VIX, the critically endangered European eel Anguilla anguilla (L.) is classified as a tolerant indicator species, and it therefore has a negative effect on classified ecological status. The scientific literature, however, suggests that eels are not generally tolerant and they benefit from similar environmental conditions as many insensitive species. VIX has been criticized for being too sensitive to the presence of eel in catch data, leading to low status clas-sifications when eels are caught in the monitoring surveys. In a case study using manipulations of historical electrofishing data, we assessed the influence of eel presence and abundance on the ecological status classifi-cation as determined by VIX. We demonstrate that reduction of eels in survey data have positive effects on the classified status, in many cases substantial effects. An increase of eels in the data had the reverse effect. Mere presence of eel had a strong negative effect, which is problematic if the aim is to increase the endangered eel population. Given the Swedish classification system where the quality element indicating the worst status is decisive, the classified ecological status of Swedish rivers can theoretically be improved by management actions disfavouring eel, unless the results from VIX are carefully evaluated by experts. Along the same lines, measures implemented with an aim to increase the endangered eel population will lead to a decrease in assessed ecological status of Swedish rivers. Our conclusion is that the usage of VIX within Swedish water management is prob-lematic and needs revision. From a broader perspective, the classification of species as generally tolerant need to be approached with great caution when developing new indices for assessing ecological status and integrity

Contrasting long-term trends in juvenile abundance of a widespread cold-water salmonid along a latitudinal gradient: effects of climate, stream size and migration strategy

A changing climate reshapes the range distribution of many organisms, and species with relatively low thermal optima, like many salmonids, are increasingly expected to face local population extinctions at lower latitudes. Understanding where and how fast these changes are happening is of pivotal importance for successful mitigation and conservation efforts.We used an extensive electrofishing database to explore temporal trends of juveniles of brown trout Salmo trutta in 218 locations from 174 Swedish streams, over the last 30 years (1991-2020). We hypothesized that 1) declines in abundance have occurred predominately in the warmer, southern regions, while increases have occurred in the colder, northern regions, 2) larger stream sizes may partly offset negative effects of climate, and 3) migrating and resident populations are affected differently by a warming climate.We found that abundance of brown trout juveniles generally declined in warmer regions especially in smaller streams (<= 6 m wide), while the abundance increased in colder regions. In larger streams, negative effects of higher temperatures were seemingly buffered, as we found lower rates of decline or even positive trends. The rate of change (i.e. the slopes of the trends in abundance) was more pronounced towards the climate extremes, and was on average zero in regions with a normal annual air temperature (average temperature over 30 year period) around 5-6 degrees C. Warmer climate had stronger effects on migrating compared to resident populations, suggesting that climate-induced loss of stream connectivity could be an additional factor that hinders recruitment in anadromous populations in a changing climate.Considering predictions of increasing temperatures and frequency of summer droughts, management of cold-water salmonid populations should focus on conserving and restoring riparian vegetation, wetlands, climate and thermal refugia, and habitat integrity overall. Such measures may, however, not suffice for small streams at lower latitudes, unless hydrological connectivity is maintained

Contrasting long-term trends in juvenile abundance of a widespread cold-water salmonid along a latitudinal gradient: effects of climate, stream size and migration strategy

A changing climate reshapes the range distribution of many organisms, and species with relatively low thermal optima, like many salmonids, are increasingly expected to face local population extinctions at lower latitudes. Understanding where and how fast these changes are happening is of pivotal importance for successful mitigation and conservation efforts. We used an extensive electrofishing database to explore temporal trends of juveniles of brown trout Salmo trutta in 218 locations from 174 Swedish streams, over the last 30 years (1991–2020). We hypothesized that 1) declines in abundance have occurred predominately in the warmer, southern regions, while increases have occurred in the colder, northern regions, 2) larger stream sizes may partly offset negative effects of climate, and 3) migrating and resident populations are affected differently by a warming climate. We found that abundance of brown trout juveniles generally declined in warmer regions especially in smaller streams (≤ 6 m wide), while the abundance increased in colder regions. In larger streams, negative effects of higher temperatures were seemingly buffered, as we found lower rates of decline or even positive trends. The rate of change (i.e. the slopes of the trends in abundance) was more pronounced towards the climate extremes, and was on average zero in regions with a normal annual air temperature (average temperature over 30 year period) around 5–6 °C. Warmer climate had stronger effects on migrating compared to resident populations, suggesting that climate-induced loss of stream connectivity could be an additional factor that hinders recruitment in anadromous populations in a changing climate. Considering predictions of increasing temperatures and frequency of summer droughts, management of cold-water salmonid populations should focus on conserving and restoring riparian vegetation, wetlands, climate and thermal refugia, and habitat integrity overall. Such measures may, however, not suffice for small streams at lower latitudes, unless hydrological connectivity is maintained.publishedVersio

Substantial Decrease in Comorbidity 5 Years After Gastric Bypass : A Population-based Study From the Scandinavian Obesity Surgery Registry

OBJECTIVE:: To evaluate effect on comorbid disease and weight loss 5 years after Roux-en-Y gastric bypass (RYGB) surgery for morbid obesity in a large nationwide cohort. BACKGROUND:: The number patients having surgical procedures to treat obesity and obesity-related disease are increasing. Yet, population-based, long-term outcome studies are few. METHODS:: Data on 26,119 individuals [75.8% women, 41.0 years, and body mass index (BMI) 42.8?kg/m] undergoing primary RYGB between May 1, 2007 and June 30, 2012, were collected from 2 Swedish quality registries: Scandinavian Obesity Surgery Registry and the Prescribed Drug Registry. Weight, remission of type 2 diabetes mellitus, hypertension, dyslipidemia, depression, and sleep apnea, and changes in corresponding laboratory data were studied. Five-year follow-up was 100% (9774 eligible individuals) for comorbid diseases. RESULTS:: BMI decreased from 42.8?±?5.5 to 31.2?±?5.5?kg/m at 5 years, corresponding to 27.7% reduction in total body weight. Prevalence of type 2 diabetes mellitus (15.5%–5.9%), hypertension (29.7%–19.5%), dyslipidemia (14.0%–6.8%), and sleep apnea (9.6%–2.6%) was reduced. Greater weight loss was a positive prognostic factor, whereas increasing age or BMI at baseline was a negative prognostic factor for remission. The use of antidepressants increased (24.1%–27.5%). Laboratory status was improved, for example, fasting glucose and glycated hemoglobin decreased from 6.1 to 5.4?mmol/mol and 41.8% to 37.7%, respectively. CONCLUSIONS:: In this nationwide study, gastric bypass resulted in large improvements in obesity-related comorbid disease and sustained weight loss over a 5-year period. The increased use of antidepressants warrants further investigation

Considerations needed for analysing data from the Swedish Electrofishing RegiSter (SERS), with special reference to the RivFishTIME database of long-term riverine surveys

The published database RivFishTIME (Comte et al. 2021, Global Ecology and Biogeography, doi: 10.1111/geb.13210) includes a large section of time-series data on fish abundance in Swedish rivers from the Swedish Electrofishing RegiSter, SERS. Knowledge about the limitations of the source data are important when extracting and analyzing data and with this brief note we provide some details that may be helpful for interpreting the Swedish time-series. The note highlights the importance of linking vital metadata to extracted focal data when constructing new databases, especially concerning time series data from monitoring programs conducted in non-randomly selected sites with human environmental impacts. Many of the SERS data come from rivers that have been affected by human impact, e.g. liming to mitigate environmental acidification and hydropower dams, since before monitoring was initiated. Data in SERS are also biased towards shallow salmonid habitats, due to the configuration of Swedish monitoring programs. Hence, data from many rivers are not representative of their fish biodiversity in general. This information is vital for appropriate interpretation of fish biodiversity trends. For RivFishTIME analyses considerations are important since Swedish data constitutes a large proportion of the database. We also provide background information about SERS and references to other Swedish databases containing complementary information. Finally, we provide contact information of the SERS database  curators, who can assist prospective analysts with data extraction from SERS

Biologiskt underlag till arbetet med Havs- och vattenmyndighetens regeringsuppdrag om förvaltning av lax och öring

Föreliggande rapport utgör biologisk rådgivning till Havs- och vattenmyndighetens regeringsuppdrag om förvaltning av lax och öring i svenska vattendrag upp till första vandringshindret. Fokus är på lax, underlag för förvaltning av öring presenteras i separat rapport. I Sverige finns två större indelningar av den havsvandrande laxen – Atlantlax på västkusten och Östersjölax i Östersjön. Laxen i vattendrag längs svenska västkusten förvaltas via NASCO (North Atlantic Salmon Conservation Organisation). För laxen i Östersjön har EU-kommissionen utformat ett förslag på internationell förvaltningsplan, men något beslut om denna förvaltningsplan har ännu inte tagits. För både Atlanten och Östersjön baseras den biologiska rådgivningen främst på Internationella Havsforskningsrådets (ICES) analyser. Förvaltningsmålen för Östersjölax och lax i Atlanten är baserade på MSY(Maximum Sustainable Yield)-principen. MSY-målet är ett produktionsmål i syfte att maximera uttaget av fisk och tar inte hänsyn till olika bevarandeaspekter. För många större laxbestånd är MSY-nivån sannolikt tillräckligt hög sett ur ett bevarandeperspektiv, där målet är att minimera risken för genetisk utarmning och/eller lokalt utdöende. För vissa mindre bestånd kan dock MSY-målet visa sig vara för lågt sett ur ett långsiktigt biologiskt bevarandeperspektiv. Denna fråga behöver utredas med hjälp av kompletterande analyser. MSY-nivån för ett visst bestånd beror på hur rekryteringsfunktionen ser ut; den senare varierar både mellan bestånd och över tid (inom bestånd). Vissa bestånd har en brant rekryteringsfunktion. Dessa bestånd kännetecknas av en jämförelsevis lägre täthetsoberoende dödlighet under sötvattensfasen, potential att snabbt tillväxa i numerär, ett relativt högt produktionsöverskott (som kan exploateras) samt att de kräver relativt sett få lekfiskar för att uppnå MSY-nivån. Bestånd med mer flacka rekryteringsfunktioner kännetecknas av högre täthetsoberoende dödlighet, långsammare beståndstillväxt, lägre produktionsöverskott vid MSY, samt att de kräver relativt många lekfiskar för att MSY-nivån ska uppnås. Förändrade målnivåer förväntas påverka olika fiskerier (hav, kust och älv) i olika omfattning, där konsekvenserna för fisket styrs av både den internationella och nationella förvaltningens regelverk. För dagens förvaltning av våra svenska laxbestånd i Östersjön innebär de internationella förutsättningarna att det är svårt att fullt ut bedriva en beståndsbaserad förvaltning, dvs. att nyttja varje enskilt laxbestånd efter dess bärkraft. Detta beror på att enbart en kvot sätts där såväl odlad som vild lax ingår. Geografiska områden kan användas i förvaltningen för att styra fisket mot de bestånd som tål beskattning, eftersom de olika bestånden fångas i olika proportioner längs olika kustavsnitt. Idag används ICES-områden till att fördela den svenska delen av laxkvoten. Dessa områden bedöms dock vara alltför stora för att effektivt kunna genomföra en beståndsbaserad förvaltning. En geografisk indelning bör utgå från mindre älvnära kustområden, eftersom blandfisket där visat sig vara litet. För icke älvnära kustfiskeområden behöver hänsyn tas till förekomsten av olika förbivandrande laxbestånd inom respektive område. Dagens överskott av återvändande kompensationsodlad lax som inte fiskas upp innebär biologiska risker och storleken på detta överskott bör minska. Ett ökat fiske efter odlad (fenklippt) lax med återutsättning av vild (oklippt) lax framstår som möjligt, men är i dagsläget ingen optimal förvaltningsåtgärd då de redskap som används ännu inte är tillräckligt skonsamma för den fisk som återutsätts. En framtida förvaltningsmodell bör förhålla sig till internationella beståndsmål, men även till nationella och mer lokala mål (vilka kan vara högre satta). Beståndsstatus och måluppfyllelse bör analyseras och utvärderas kontinuerligt, varefter nödvändiga åtgärder kan övervägas. En framtida ekosystembaserad beståndsvis och adaptiv förvaltning bör innehålla följande moment; utvärdering av status/måluppfyllelse, problemanalys, införande av åtgärder, uppföljning och tillsyn, datainsamling, dataanalys och utvärdering av åtgärder. Beståndsbaserad förvaltning ställer höga krav på både forskare, förvaltare och nyttjare av resursen. Detta innebär att det för både östersjö- och atlantlaxen kommer att krävas ökade resurser till datainsamling och analys för att kunna tillgodose förvaltningens behov av adekvat biologisk rådgivning på beståndsnivå